拭子法筛选抗菌药物敏感菌种和最适培养基

Screening Sensitive Strain and Optimal Medium against Antimicrobial Agents with Cotton Swabs

以抑菌圈直径大小和最低检测限为衡量标准，筛选敏感菌种和最适培养基，为饲料与食品中抗菌药物残留的高通量快速检测提供参考。试验以枯草芽孢杆菌（Bacillus subtilis）CMCC63501、巨大芽孢杆菌（Bacillus megaterium）ACCC10245和藤黄微球菌（Micrococcus luteus）CMCC（B）28001为测试菌，采用MH琼脂、培养基Ⅰ、抗生素检定用培养基（AM-5）为检测用培养基。结果表明，以枯草芽孢杆菌CMCC63501和MH琼脂为组合搭配时，除了氟苯尼考（2．0μg／ml）和泰乐菌素（0．4μg／ml）外，环丙沙星、恩诺沙星、红霉素和金霉素在磷酸盐缓冲液中的最低检测限均低于中国规定的最高检测限量（MRL）。环丙沙星、恩诺沙星和红霉素在磷酸盐缓冲液中的线性范围为0．05～0．80μg／ml、金霉素为0．075～2．00μg／ml时，相关系数分别达到0．9967、0．9936、0．9947、0．9953。结果提示，对环丙沙星、思诺沙星、红霉素、金霉素4种抗菌药物的最敏感菌种是枯草芽孢杆菌CMCC63501，最适培养基为MH琼脂。对氟苯尼考和泰乐菌素的检测限未达到国家规定的MRL，CMCC63501和MH培养基组合尚待进一步研究完善。

A method was developed to provide scientific references for sensitive strain screening against antimicrobial residues in animal tissue based on the size of inhibition zone and the limit of detection. Bacillus subtilis CMCC63501, Bacillus megaterium ACCC10245 and Micrococcus luteus CMCC（ B）28001 were used as testing bacteria, and MH agar, medium Ⅰ, and antibiotic Medium-5 as, testing media. Except for florfenicol and tylosin, the detected limits of ciprofloxacin, enrofloxaein, erythromycin and chlortetracycline against B. subtilis CMCC63501 in phosphate buffer solution （PBS） on MH agar were lower than maximum residue levels （MRLs） established in China. Standard curves between 0. 05 -0. 80 μg/ml of antimicrobial agents such as ciprofloxaein, enrofloxacin and erythromycin and 0. 075 - 2. 00 μg/ml of chlortetracy-eline and B. subtilis in PBS were obtained, the correlation coefficient being 0. 996 7, 0. 993 6, 0. 994 7, and 0. 995 3, respectively. The results suggested that the efficacy of ciprofloxacin, enrofloxacin, erythnomycin and chlortetracycline exhibited the strongest on MH agar medium against B. subtilis CMCC63501. However, because the detection limit of florfenied and tylosin could not reach the MRL, the combination of B. subtilis CMCC63501 and MH agar medium needed to be to improved.